1. Field of the Invention
The present invention relates to a magnetic disk device and, more particularly, to a magnetic disk device using a hard disk.
2. Description of the Related Art
Magnetic disk devices have been in widespread use and are popular as external storages. A magnetic disk device includes a magnetic disk, a motor for rotating the magnetic disk, a slider radially movable along the magnetic disk, and a magnetic head mounted on the slider to perform data read and write operations with respect to the magnetic disk.
In a prior art magnetic disk device using a hard disk, a magnetic head floats above the magnetic recording surface of the hard disk during data read/write accessing of the hard disk. More specifically, the slider for supporting the magnetic head thereon has a shape which generates an airflow between the slider and the hard disk. The slider connected to the magnetic head is subject to a dynamic pressure generated by an airflow such that the slider floats above the magnetic recording surface of the hard disk at a predetermined distance. For example, the slider receives a predetermined force from a means such as a spring element and is urged toward the hard disk. The slider, and hence the magnetic head, are located in a floating position where the biasing force of the spring is balanced with the slider's dynamic pressure generated by the airflow.
A large demand has arisen in recent years for a magnetic disk device which increases the recording density of the magnetic disk. In order to respond to this demand, a vertically magnetized recording system has been proposed. If this system is applied to the conventional magnetic disk device of a hard disk type, the distance between the magnetic recording surface of the hard disk and the magnetic head must be 0.1 .mu.m or less. Variations in this distance must be minimized as much as possible.
Since the slider of the prior art magnetic disk device floats above the magnetic recording surface of the hard disk by means of the dynamic pressure of the airflow generated between the slider and the hard disk, the floating position of the slider, i.e., of the magnetic head, varies greatly in accordance with disturbances such as vibrations which act upon the magnetic disk device. It is, therefore, impossible under prior methods to reduce the distance between the magnetic head and the magnetic recording surface of a hard disk since variations in distance therebetween must be kept within the allowable range. As a result, even if a vertically magnetized recording method is used, the recording density cannot be sufficiently increased.
Further, when the disk is static, the air bearing surface of the slider is put in contact with the magnetic recording surface of the disk. Thus, when the rotation of the disk is started or stopped, a largely varying contact force is produced between the air bearing surface of the slider and the magnetic recording surface of the disk. Since the disk is rotated and stopped frequently, the magnetic recording surface of the disk may considerably be damaged by the repeated application of the largely varying contact force.